1. Safe Browsing at SIIT

2. the Internet Explain web browsing and Internet structure
Here is the web page
containing your news feeds
Response
Send me the web page
of my news feeds
the Internet
Request
wsiit
Explain web browsing and Internet structure
You - WiFi AP - Internet - Server
Send request for web page
Receive web page in response

3. the Internet Another example of web browsing, this time with login
Login as
with mysEcretpassw0rd
the Internet
Request
wsiit
Another example of web browsing, this time with login
Response
Here is the web page
for registration

4. Can someone else see the web pages you are visiting?

5. the Internet
wsiit
Demo of wireless packet capture

7. Request
Request
Response
Response

8. When using WiFi, assume everyone nearby can “see” everything you do on the Internet
the websites you visit:
the information on web pages: Account balance = 1,000,000,000 Baht
the comments you post: Dr Steve is the worst lecturer ever!
the passwords you submit: , mysEcretpassw0rd

9. unless you use encryption
When using WiFi, assume everyone nearby can “see” everything you do on the Internet
unless you use encryption
WiFi Encryption: WPA
Web Browsing Encryption: https

10. Encryption changes the message so that
only those with the same key can read it
Encrypt with key
Request
a6i#l)P1
a6i#l)P1
9G<3t_da;
9G<3t_da;
Decrypt with key
Response

11. Use HTTPS when accessing “important” websites
Use WPA in your own
WiFi network

12. Man-in-the-Middle Attack on HTTPS
Facebook thinks
I am you
You think I am Facebook
fake_wsiit
Facebook gives “you” ( ) the key
You receive the key from “Facebook” ( )
Everything encrypted with the key can be decrypted
by attacker ( )

13. Beware of security warnings!
Especially for websites that don't
normally give a warning

14. Use your powers for good
Safe Browsing with WiFi
Assume everyone can see what you are doing
Use HTTPS when accessing “important” websites
Use WPA in your own WiFi network
Beware of security warnings when using HTTPS
Use your powers for good Bi
Sam
Dana
Steve
Linux
mitmproxy